<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
//                                                             //
// module.audio.dts.php                                        //
// module for analyzing DTS Audio files                        //
// dependencies: NONE                                          //
//                                                             //
/////////////////////////////////////////////////////////////////


/**
 * @tutorial http://wiki.multimedia.cx/index.php?title=DTS
 */
class getid3_dts extends getid3_handler
{
    /**
     * Default DTS syncword used in native .cpt or .dts formats
     */
    const syncword = "\x7F\xFE\x80\x01";

    private $readBinDataOffset = 0;

    /**
     * Possible syncwords indicating bitstream encoding
     */
    public static $syncwords = array(
        0 => "\x7F\xFE\x80\x01", // raw big-endian
        1 => "\xFE\x7F\x01\x80", // raw little-endian
        2 => "\x1F\xFF\xE8\x00", // 14-bit big-endian
        3 => "\xFF\x1F\x00\xE8"); // 14-bit little-endian

    public function Analyze()
    {
        $info = & $this->getid3->info;
        $info['fileformat'] = 'dts';

        $this->fseek($info['avdataoffset']);
        $DTSheader = $this->fread(20); // we only need 2 words magic + 6 words frame header, but these words may be normal 16-bit words OR 14-bit words with 2 highest bits set to zero, so 8 words can be either 8*16/8 = 16 bytes OR 8*16*(16/14)/8 = 18.3 bytes

        // check syncword
        $sync = substr($DTSheader, 0, 4);
        if (($encoding = array_search($sync, self::$syncwords)) !== false) {

            $info['dts']['raw']['magic'] = $sync;
            $this->readBinDataOffset = 32;

        } elseif ($this->isDependencyFor('matroska')) {

            // Matroska contains DTS without syncword encoded as raw big-endian format
            $encoding = 0;
            $this->readBinDataOffset = 0;

        } else {

            unset($info['fileformat']);
            return $this->error('Expecting "' . implode('| ', array_map('getid3_lib::PrintHexBytes', self::$syncwords)) . '" at offset ' . $info['avdataoffset'] . ', found "' . getid3_lib::PrintHexBytes($sync) . '"');

        }

        // decode header
        $fhBS = '';
        for ($word_offset = 0; $word_offset <= strlen($DTSheader); $word_offset += 2) {
            switch ($encoding) {
                case 0: // raw big-endian
                    $fhBS .= getid3_lib::BigEndian2Bin(substr($DTSheader, $word_offset, 2));
                    break;
                case 1: // raw little-endian
                    $fhBS .= getid3_lib::BigEndian2Bin(strrev(substr($DTSheader, $word_offset, 2)));
                    break;
                case 2: // 14-bit big-endian
                    $fhBS .= substr(getid3_lib::BigEndian2Bin(substr($DTSheader, $word_offset, 2)), 2, 14);
                    break;
                case 3: // 14-bit little-endian
                    $fhBS .= substr(getid3_lib::BigEndian2Bin(strrev(substr($DTSheader, $word_offset, 2))), 2, 14);
                    break;
            }
        }

        $info['dts']['raw']['frame_type'] = $this->readBinData($fhBS, 1);
        $info['dts']['raw']['deficit_samples'] = $this->readBinData($fhBS, 5);
        $info['dts']['flags']['crc_present'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['raw']['pcm_sample_blocks'] = $this->readBinData($fhBS, 7);
        $info['dts']['raw']['frame_byte_size'] = $this->readBinData($fhBS, 14);
        $info['dts']['raw']['channel_arrangement'] = $this->readBinData($fhBS, 6);
        $info['dts']['raw']['sample_frequency'] = $this->readBinData($fhBS, 4);
        $info['dts']['raw']['bitrate'] = $this->readBinData($fhBS, 5);
        $info['dts']['flags']['embedded_downmix'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['flags']['dynamicrange'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['flags']['timestamp'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['flags']['auxdata'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['flags']['hdcd'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['raw']['extension_audio'] = $this->readBinData($fhBS, 3);
        $info['dts']['flags']['extended_coding'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['flags']['audio_sync_insertion'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['raw']['lfe_effects'] = $this->readBinData($fhBS, 2);
        $info['dts']['flags']['predictor_history'] = (bool)$this->readBinData($fhBS, 1);
        if ($info['dts']['flags']['crc_present']) {
            $info['dts']['raw']['crc16'] = $this->readBinData($fhBS, 16);
        }
        $info['dts']['flags']['mri_perfect_reconst'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['raw']['encoder_soft_version'] = $this->readBinData($fhBS, 4);
        $info['dts']['raw']['copy_history'] = $this->readBinData($fhBS, 2);
        $info['dts']['raw']['bits_per_sample'] = $this->readBinData($fhBS, 2);
        $info['dts']['flags']['surround_es'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['flags']['front_sum_diff'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['flags']['surround_sum_diff'] = (bool)$this->readBinData($fhBS, 1);
        $info['dts']['raw']['dialog_normalization'] = $this->readBinData($fhBS, 4);


        $info['dts']['bitrate'] = self::bitrateLookup($info['dts']['raw']['bitrate']);
        $info['dts']['bits_per_sample'] = self::bitPerSampleLookup($info['dts']['raw']['bits_per_sample']);
        $info['dts']['sample_rate'] = self::sampleRateLookup($info['dts']['raw']['sample_frequency']);
        $info['dts']['dialog_normalization'] = self::dialogNormalization($info['dts']['raw']['dialog_normalization'], $info['dts']['raw']['encoder_soft_version']);
        $info['dts']['flags']['lossless'] = (($info['dts']['raw']['bitrate'] == 31) ? true : false);
        $info['dts']['bitrate_mode'] = (($info['dts']['raw']['bitrate'] == 30) ? 'vbr' : 'cbr');
        $info['dts']['channels'] = self::numChannelsLookup($info['dts']['raw']['channel_arrangement']);
        $info['dts']['channel_arrangement'] = self::channelArrangementLookup($info['dts']['raw']['channel_arrangement']);

        $info['audio']['dataformat'] = 'dts';
        $info['audio']['lossless'] = $info['dts']['flags']['lossless'];
        $info['audio']['bitrate_mode'] = $info['dts']['bitrate_mode'];
        $info['audio']['bits_per_sample'] = $info['dts']['bits_per_sample'];
        $info['audio']['sample_rate'] = $info['dts']['sample_rate'];
        $info['audio']['channels'] = $info['dts']['channels'];
        $info['audio']['bitrate'] = $info['dts']['bitrate'];
        if (isset($info['avdataend']) && !empty($info['dts']['bitrate']) && is_numeric($info['dts']['bitrate'])) {
            $info['playtime_seconds'] = ($info['avdataend'] - $info['avdataoffset']) / ($info['dts']['bitrate'] / 8);
            if (($encoding == 2) || ($encoding == 3)) {
                // 14-bit data packed into 16-bit words, so the playtime is wrong because only (14/16) of the bytes in the data portion of the file are used at the specified bitrate
                $info['playtime_seconds'] *= (14 / 16);
            }
        }
        return true;
    }

    private function readBinData($bin, $length)
    {
        $data = substr($bin, $this->readBinDataOffset, $length);
        $this->readBinDataOffset += $length;

        return bindec($data);
    }

    public static function bitrateLookup($index)
    {
        static $lookup = array(
            0 => 32000,
            1 => 56000,
            2 => 64000,
            3 => 96000,
            4 => 112000,
            5 => 128000,
            6 => 192000,
            7 => 224000,
            8 => 256000,
            9 => 320000,
            10 => 384000,
            11 => 448000,
            12 => 512000,
            13 => 576000,
            14 => 640000,
            15 => 768000,
            16 => 960000,
            17 => 1024000,
            18 => 1152000,
            19 => 1280000,
            20 => 1344000,
            21 => 1408000,
            22 => 1411200,
            23 => 1472000,
            24 => 1536000,
            25 => 1920000,
            26 => 2048000,
            27 => 3072000,
            28 => 3840000,
            29 => 'open',
            30 => 'variable',
            31 => 'lossless',
        );
        return (isset($lookup[$index]) ? $lookup[$index] : false);
    }

    public static function sampleRateLookup($index)
    {
        static $lookup = array(
            0 => 'invalid',
            1 => 8000,
            2 => 16000,
            3 => 32000,
            4 => 'invalid',
            5 => 'invalid',
            6 => 11025,
            7 => 22050,
            8 => 44100,
            9 => 'invalid',
            10 => 'invalid',
            11 => 12000,
            12 => 24000,
            13 => 48000,
            14 => 'invalid',
            15 => 'invalid',
        );
        return (isset($lookup[$index]) ? $lookup[$index] : false);
    }

    public static function bitPerSampleLookup($index)
    {
        static $lookup = array(
            0 => 16,
            1 => 20,
            2 => 24,
            3 => 24,
        );
        return (isset($lookup[$index]) ? $lookup[$index] : false);
    }

    public static function numChannelsLookup($index)
    {
        switch ($index) {
            case 0:
                return 1;
                break;
            case 1:
            case 2:
            case 3:
            case 4:
                return 2;
                break;
            case 5:
            case 6:
                return 3;
                break;
            case 7:
            case 8:
                return 4;
                break;
            case 9:
                return 5;
                break;
            case 10:
            case 11:
            case 12:
                return 6;
                break;
            case 13:
                return 7;
                break;
            case 14:
            case 15:
                return 8;
                break;
        }
        return false;
    }

    public static function channelArrangementLookup($index)
    {
        static $lookup = array(
            0 => 'A',
            1 => 'A + B (dual mono)',
            2 => 'L + R (stereo)',
            3 => '(L+R) + (L-R) (sum-difference)',
            4 => 'LT + RT (left and right total)',
            5 => 'C + L + R',
            6 => 'L + R + S',
            7 => 'C + L + R + S',
            8 => 'L + R + SL + SR',
            9 => 'C + L + R + SL + SR',
            10 => 'CL + CR + L + R + SL + SR',
            11 => 'C + L + R+ LR + RR + OV',
            12 => 'CF + CR + LF + RF + LR + RR',
            13 => 'CL + C + CR + L + R + SL + SR',
            14 => 'CL + CR + L + R + SL1 + SL2 + SR1 + SR2',
            15 => 'CL + C+ CR + L + R + SL + S + SR',
        );
        return (isset($lookup[$index]) ? $lookup[$index] : 'user-defined');
    }

    public static function dialogNormalization($index, $version)
    {
        switch ($version) {
            case 7:
                return 0 - $index;
                break;
            case 6:
                return 0 - 16 - $index;
                break;
        }
        return false;
    }

}
